It will take roughly 45 minutes to an hour to have them fully charged and of course with Fast Fuel, 5 minutes of charging gets you more or less 2 hours of playback. Important to know, as it is not clearly mentioned in the documentation, while charging the light will be red and "breathing", once fully charged it will turn white.

Most bluetooth audio device will lag about 1 second at the beginning of a video. I find this problem in my Momentum in Ear Wireless headphone and Bose Touch Soundlink speaker, but I didn't notice it on beatsX! I think it owes to W1 chip.